Process of treating extracts of quebracho.



- obtained by hot extraction (diffusion), which.

a turbid appearance.

For carrying out in practice the part above UNITED STATES PATENT OFFICE.

LEOPOLD POLLAK, OF WILSDORF, NEAR BO DENBACH, AUSTRIA-HUNGARY, ABSIGNOR OF ONE- HALF TO ALBERT BEDLICH, OF WILBDORF, NEAR BODENBAGH, AUSTRIA-HUNGARY.

v PROCESS OF TREATING EZ'IBAO'IS OF QUEBBAOEO.

No. 000,088. Y

To all whom it my concem:

Be it known that I, LEOPOLD POLLAK, subject of the Em eror of Austria-Hungaig, residin at Wils orf,'. near Bodenba'c ohemia, ustria-Hungary, have invented certain new and useful Improvements in Processes of Treating Extracts of'Quebracho, of which the following is a specification.

This invention relates to a process by means of which the quebracho liquid extracts as is well known, contain a more or less considerable quantity of slightl soluble tanning substances, the so-called phlobaphenes, are perfectly purified and clarified with the em ployment of very smallquantities of alkali. oreover the said rocess renders it possible to make easily soluble the tanning substances that are contained in the said liquidextracts and are slightly soluble, to recover all substances that are'capable to have a tannin action and to convert them into a clear an easily soluble condition. For attaining this purpose the hot liquid that is obtained by hot extraction is allowed to cool down, in consequence of which a mud is precipitated from.

which the liquidthat is standing above the same is sefparated. The mudwh1ch consists mostly 1'0 resin-like strongly colored sub-' stances slightly solublein water can be saponified and rendered easily soluble by means of very small quantities of alkali and in this condition-it has the propert to comgletely" clarify the liquid which as been rained off from the mud and which has still referredto'of the process that forms the subject matter of the presentinvention, to the mud originating fromithe liquid that is obtained by .hot extractionfrom uebracho wood, by allowing thisli uid to coo is added 9. small quantityof an a kali for instance of a solution of potash or of soda. The mixture is then maintained for several hours at a temperature of from to 100. C. and durin the whole time it is thoroughly stirred and t 's is continued until a solution is obtained which also in a cooled condition possesses a clear deep red coloration. The quantity of the alkali that is to be added as well as the durationof the heating of the stirredup mud should be determined empirically by tests. It has been ascertained by experience that in the majority of cases one part byweight of Specification of Letters Patent. Application filed December 80, 1007. Serial No. $07,041.

' Patented Sept. 29, 1908.

the alkali to 1000 parts by wei ht of the on?- nal liquid treated and that a uration of t e '0 eration of from 6 to 7 hours are sufficient.

o the liquid separated from the mud as above indicated is then added the said deep red solution in a uantity that is to be determined by tests an during this olperation the mixture is thoroughly stirred. xperiments have shown that as a general rule it is suflicient to add to 1000 liters of the drained off liquid about 50 liters of the deep red solution in order to obtain immediately an abundant deposit of flakes. After the apse of 'a few hours the li uid is perfectly clear while on the bottom of t e vessel a solid precipitate is deposited which lapbll having been dissolved afigin by the a dition of water and of an a ali in the manner above indicated with reference to the treatment of the mud and by heating for a ,sufiicientl lo duration can now be utilized for the c arifymg of a further quantity of fresh quebracho liquid obtained by hot extraction after it has been separated from the mud.

The clear li uid obtained-in the manner above describe and remaining on the top of the mud can be concentrated by evaporation be converted into a dry condition. It forms the pure quebracho extract soluble in cold water and distinguished b special clearness.

For the execution of t e process as .described until now only a part of the mud has been employed that contains phlobaphenes and that isformed in the first part of the process. It is however important to enable the utilization of the remamin part of the mud for tanning urposes in or M -it possible to app y with advant e ,alltanning principles contained in the, quid extract of quebracho. For this purpose it is only necessary to-mix-intimately the remaining part of the deep red-solution which has been obtained from the first portion of .the mud by the addition of alkali and by heat er to render I with tanning liquids of a high acidity oks tained from sumach or other leaves,

or woods and which are notoriously easily soluble: In con uence of this operation the phlobaphenes con ained in the said'red solution are converted into a condition in which they are soluble in cold water. The percentage of acid contained in these liquids should correspond more or less to the percentage of about 120 kilo alkali contained in the red solution and in case this percentage of acid should not present in the extracts of the barks etc. in their natural state it can be produced by the addition of suitable acids as for instance of acetic acid.

When the red solution is mixed with the liquid possessing a suitable acidity the mixture becomes turbid and conse uently it must be left to stand until the tui bidity disa pears in conse uence of the precipitation oi the insoluble su stances. The precipitate thus formed consists only of substances that are ineffective for tanning pu oses and insoluble in water and the c ari (1 liquid in which all substances that have a tanning action are contained in a clear solution, after its se ar'ation from the said precipitate, can now he evaporated to the degree of density re uired for the extract.

example of the complete process may be described as follows:From 2000 kiloams of quebracho wood are obtained after t e extraction 2000 liters of turbid liquor and 200 kilograms of sediments when the li nor has, cooled down to 25 C. The 200 kilograms of the sediment are mixed with a solution of 2 kilogr. of calcined sodium carbonate, whereb a solution of the sediments takes place an only an insoluble sediment of particles of wood remains undissolved. Of this solution of the sediment 100 liters are added to the 2000 liters of the turbid extract liquor above indicated, the mixture is stirred and the flaky precipitateformed during this operation is al owed to de osit. This deposit will form a coherent ca e' of ams. Theclear liquor is then evaporate while the Precipitated part is mixed with the excess 0 the solution obtainedfrom the sediment of the first operation and to this is added 1 kilogr. more of the dissolved calcined sodium carbonate. The whole mixture is then digested duri 5 hours at a temperature of C. In this manner 200 liters of a solution are obtained 'to whicha decoction of 50 kilograms of sumach or 80 kilo of pine bark or of hemlock bark are a ded and besides in order to increase the speed of the work, 1 liter of acetic acid may be added. A recipitate is then separated that deposits within 12 to 15 hours into a solid'sediment which cannot be submitted to any further treatment and is removed as refuse, whereas the clear solution which contains all entsis submitted to evaporation.

It is most probable that by means of the practically useful ingrediabove described the phlobaphenes contained not 0 y in the required extracts of quebracho but also in other slightly soluble tanning extracts can be converted into a condition in which they are easily soluble in cold water.

Claim.

1. The herein described process of clarifying li uid extracts of quebracho wood and for ren ering them soluble in cold water, which consists in separating the mud from the liquidwhich stands above the same after extraction, adding a small quantity of alkali and water to the mud after such separation and appl i heat, and adding' a uantit of the sol uiz fim thus obtained to tli e liquid priviously separated from the mud to form a es.

2. The herein described process of clarifyi extracts of quebracho wood and for ren erl water w 'ch consists in a hot extraction to form a mud and liquid after cooling, saponifying and rendering soluble said mud by the addition thereto of a small quantity of alkali and water and heati the resultant solution, and adding to said solution a quantity of the li uid previously drawn off from the mud to orm flakes, the deposit of which leaves a liquid extract which may be drawn ofl in a clear condition.

3. The herein described process of clarifyin extracts of quebracho wood-and for ren ering the tanning principles soluble in cold water which consists in adding a small quantity of alkali and water to the mud which is obtained after 0001' of the liquid obtained by hot extraction ter such mud has been separated from the liquidwhich stands above the same, and a plymg heat to such solution, adding a s cient quantity of the solution thus obtained to the liquid previously drawn off from the mud to form akes from which the liquid extract is drawn oil in a clear condition after the deposit of the flakes, and-fendering the phlobaphenes contained in the remaining parts of the mud soluble in cold water b with the solution obtained from t e mud a quantity of alkali, and heating the tanning extracts or liquids of higher acidity.

In testimony whereof I have ereunto set my hand in presence of two subscribing witnesses.

LEOPOLD POLLAK. Witnesses AnoLrn' Frsonna, An'rmm Somro.

latter mixture with the same easily soluble in cold 

